Our long-term goal is to understand behavior and social interactions as processes of adaptation to the problems that individuals face in their natural environment. The research is carried out on free-ranging primates, primarily the baboon population of the Amboseli National Park, Kenya, which is the subject of a series of ongoing studies by P.I. and his colleagues. Research to be undertaken during the next five years includes both field studies of primates, and research on theory and analysis of primate social systems and ecology. The field research will focus on ecology of feeding and foraging behavior (six projects), maternal behavior and infant development (five projects), demographic causes and effects of behavior, and the long-term stability of social bonds. Theoretical studies include work on methodological and statistical problems in behavioral ecology, axiomatic treatment of mating systems, and a monograph on primate behavior and ecology. The research involves systematic sampling of behavior by direct observation, biochemical analysis of primate foods for nutrients and toxins, and development of quantitative models for behavioral and ecological processes.